Must insulation between transformers and silicon steel sheets be made?
If the iron core is a whole, it is equivalent to a large area of conductor, the circuit is short, and its resistance is very small, although the induction voltage is not high, but the current is very large. This gives rise to a great eddy (circulation) loss. This is very disadvantageous to the transformer. In severe cases, rapid heating of the metal results in partial melting of the core, called the iron core".
But in practice, it is impossible to achieve complete insulation due to problems such as manufacturing process (especially in the case of maintenance history). But even in this case, the contact resistance between the silicon steel sheet is much larger than that of making the whole piece of internal resistance, and it also plays a certain role in reducing the eddy current.
Ideally, the transformer silicon steel sheet must be insulated.
After each piece is coated with insulating paint, the core is split into many small cross sections at the resulting cross section. In this way, the resistance becomes larger. Therefore, although the coating iron core of the existence of eddy current loss (part of the iron consumption), but much smaller than before.
